If you are using the internal oven give it time The old brain says there may have been another circuit that also needed time.
On Tue, Mar 9, 2010 at 8:52 PM, Bob Camp <[email protected]> wrote: > Hi > > I didn't leave it on for very long. IIt would not surprise me if there's > some drift that's occurred. It was last calibrated in 2006. > > Bob > > > On Mar 9, 2010, at 8:48 PM, paul swed wrote: > > > Bob how long has it been on > > I think it needs to be stable like about 30 minutes > > > > On Tue, Mar 9, 2010 at 8:37 PM, Bob Camp <[email protected]> wrote: > > > >> Hi > >> > >> Ok, the trigger level pots are bent but functional. The one that was > stuck > >> works after a bit of readjustment of the knob. > >> > >> All three inputs (ext arm, and the two channels) blink when I put the > 10 > >> MHz into them. The two with the working pots behave as expected as the > pot > >> is turned (trigger in the middle, no trigger on both ends). > >> > >> For what ever reason it seems to think that the period of it's 10 MHz > >> standard is 99.5 ns. In frequency mode it thinks the standard is at > 9.998xxx > >> MHz. Obviously it's a little confused .... > >> > >> Sounds like it's worth working on, unless the 99.5 ns thing indicates > some > >> sort of massive failure. > >> > >> Bob > >> > >> > >> On Mar 9, 2010, at 7:03 PM, Mark Sims wrote: > >> > >>> > >>> I've had the "pleasure" of fixing way too many 5370A and 5370B front > >> panels. It's been a while so these musings may be clouded... also > beware > >> of the two or three different front panel designs. Also there are > "hybrid" > >> 5370A's out there with 5370B front ends. > >>> > >>> There are 4 pots on the front panel: the 470K display update rate, a > >> 10K or 200 ohm arming level (200 ohm on 5370B and later 5370A's), and > two > >> 5K trigger level. All are linear taper, all have switches, all are > small > >> pots with (1/4"? bushings). Finding pots with proper switches ain't > easy. > >>> > >>> I have never had to do the trigger level pots. They have metal shafts > >> and seldom break. Their switches are what you would expect (closed when > the > >> pot is turned clockwise). In the far CCW direction the switch is open > and > >> selects the 0V trigger level. > >>> > >>> The other two pots are an exceedingly crappy hp design. They have > >> fragile plastic shafts and really poor quality switches. The switches > need > >> to be closed when the switch is counterclockwise. HP's pots have both > >> normally open and normally closed contacts. Frankly these pots are > seldom > >> used and you can use a switchless pot and just hardwire those pads. > >>> > >>> The display rate pots is particularly useless. You can just hardwire > it > >> to max. > >>> > >>> The biggest bugaboo in buying a 5370 is the state of the HP custom > input > >> amplifier chips. They can be damaged by overloading the input. Blow > one > >> and you are screwed. Buy a 5370 with a blown input amp and you are > screwed. > >> The 5370A and 5370B used different chips. The 5345A counter is a > source > >> of input amp chips. > >>> > >>> It would be VERY nice if some clever person built drop in replacement > >> "chips" built of modern SMD parts on a DIP header. Those input amp > chips > >> are socketed. They are little more than a comparator. > >>> > >>> Quick check of the 5370A inputs is to set the unit to "SEParate" inputs > >> and connect the back panel 10 MHz ref signal to each of the inputs. The > >> signal level LED should flash. A steady LED means that input is toast > (or > >> the input PCB slide switches are full of navel lint and need cleaning). > >>> _________________________________________________________________ > >>> Hotmail: Free, trusted and rich email service. > >>> http://clk.atdmt.com/GBL/go/201469228/direct/01/ > >>> _______________________________________________ > >>> time-nuts mailing list -- [email protected] > >>> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >>> and follow the instructions there. > >>> > >> > >> > >> _______________________________________________ > >> time-nuts mailing list -- [email protected] > >> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
